Automatic slack-adjuster for brakes.



H. F. WOOD & J. GULLAGE.

AUFOMATIC SLACK ADJUSTER FOR BRAKES APPLICATION men JULY 29.1914.

1,144,453. Patented June 29, 1915.

2 SHEETS-SHEE 1. P T

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H. F. WOOD & J. GULLAGE.

AUTOMATIC SLACK ADJUSTER FOR BRAKES.

APPLICATION FILED JULY 29, 1914.

1,144,453., Patented June 29, 1915.

2 SHEETS-SHEET 2.

HERBERT F. WOOD AND JOSEPH GULLAGE, OF SOMERVILLE, MASSACHUSETTS.

AUTOMATIC SLACK-ADJUSTER FOR BRAKES.

Specification of Letters Patent.

Patented June 29, 1915.

Application fil ed July 29, 1914. Serial No. 853,966.

To all whom it may concern Be it known that we, HERBERT F. W001) andJosnrn GULLAGE, of Somerville, in the county of Middlesex and State ofMassachusetts, have invented certain new and useful Improvements inAutomatic Slack- Adjusters for Brakes, of which the following is aspecification.

The object of the present invention is to provide simple and effectivemeans by which the wear of brakes or brake shoes and other parts of abrakingmechanism may be taken up as soon as the space between the brakeand the wheel on which it acts becomes, when the brake is relaxed, morethan a certain amount.

The invention has particular reference to the braking appliances ofrailway rolling stock, wherein the brakes are provided with metal shoeswhich are subject to great and rapid wear, and are retained in use untilworn out before being discarded. Such shoes when new are givenconsiderable thickness in order that their life may not be so short asto require constant renewal, and as a consequence, the amount of stockwhich may be removed before they are worn out is so great thatrelatively large spaces are finally left between the wheels and shoes inthe relaxed position of the brakes, re-' quiring correspondingly greatmotion of the brake-operating mechanism every time the brakes areapplied to the wheels. It is desirable that this wear should be taken upin order to avoid the excessive motion of the operating mechanism causedthereby, and with this 'end in view we have devised an' improved form ofmechanism forv shifting the fulcrum of oneof the brake leversautomatically as soon as excessive wear occurs and'by'amounts suflicientto take up such wear.

Referring to the drawings,Figure ,1 represents a partial plan view of arailway truck with a slack adjuster embodying'the invention appliedthereto; Fig. 2 is a longitudinal sectional view on line 2-.-2 of Fig.

1; Fig. 3 is an elevation of a portion of the mechanism shown by; Fig.2, looking from the opposite side; "Fig. 4' is a view' similar to Fig.1,showing a different embodiment of the invention; Fig. 5 is a detailsectional view on line 55 of Fig. 4.

The same reference characters indicate the same parts in'all thefiguresf Referring first to-the embodiment ofthe invention shown byFigs. 1, 2 and 3 of the drawings, the characters 1 and 2 represent thewheels on one side of the truck, such wheels being mounted upon axles 3and 4 respectively. The truck represented is one of the common orstandard four-wheel trucks in which there are two sets of brakes, oneset for each pair of wheels arranged at respectively opposite sides ofthe wheels. At the ends of the truck are brake beam 5 and 6 carrying ontheir ends the brake heads 7 and 8, which are provided with detachablebrake shoes 9 and 10 arranged to bear directly against the rims of theseveral wheels. The brake beams are hung in the manner usual in thistype of truck and are held yieldingly away from the Wheels preferably bygravity.

As here shown, the brake heads are loosely supported by oscillatorylinks 12 pivoted at their lower ends to said heads and at their upperends to fixed supports such as cars 13 on the truck frame.

The brake beams are loosely supported by links 14 pivoted at their lowerends to arms 15 attached to the brake beams, and at their upper ends tofixed supports such as brackets 16 on the truck frame. The arrangementis such that when the brake shoes are relaxed they tend to swing awayfrom the peripheries of the wheels by gravity.

The brake beam arms'15 are preferably slotted to receive levers 18, 19,which are connected with said arms by fulcrum pins 20,21, each leverhaving a shorter and a longer arm. A brake rod 22 is connected to thelonger arm of the lever 18 and may be operated, as usual, either bycompressed air of the air brake system, or by a hand-bralc ingapparatus. The shorter arms of the levers 18 and 19 are connected by arod 23,

which transmits motion from one lever to the other.

The brake rod 22 is moved in the direction of the arrow as (Fig. 2) to'set' the brakes,-and first acts through the lever 18 and itsconnections wit the shoe 1O tomove the said shoe in the irection ofarrow 3/, thus applying'said shoe to the wheel 2 and rendering thefulcrum 20 stationary, and then acts through the rod 23, lever 19, andthe connections between said lever and the brake shoe 1%), to move saidshoe in the directionof arrow 2' and apply it to the'wheel 1. 'Thelonger ,ariii'of the lever 19 is connected with thetruck frame by atether 25,

which is preferably a short chain attached at one end to the lever 19and at the other end to a wheel or pulley 26 journaled in fixed bearingson the truck frame, said bearings being preferably formed in a bracket27 attached to the truck frame.

Mounted to oscillate on the shaft of the pulley 26 is an arm 28 carryinga pawl 29 engaging a ratchet 30 attached to said shaft. A rod 31connected with the outer end of the arm 28 has a bent end 31 having anorifice through which the brake rod 22 passes loosely. The brake rodhasan adjustable collar or projection 82 secured to it by a set screw 33,and adapted to abut against the bent end 31'" and more the rod 31 in thedirection of the arrow .1 and the arm 28 in the direction of arrow as,when the brake rod is-moved to set the brakes. The arrangement of theteeth of the ratchet 30 and of the pawl 29 is such that the describedmovement of the arm 28 moves the pawl backwardly on the ratchet.

When the brake shoes are new and un- Worn the collar 32 is adjusted sothat it will not be brought. into contact with the bent end 31 by the.brake-setting movement of i the rod 22. The amplitude of the brakesetting movement of the rod22 is gradually increased by wear of thebrake shoes until it is sufiicien't to cause the collar 32 to impart thedescribed movement to the arm 28 and pawl 29. When said movement becomessufiicient to move the pawl a distance slightly greater than the lengthof one tooth of the ratchet 30, the pawl takes anew hold of the ratchetso that when the brake rod 22 is released a spring 35 acts on a rod 36connected with the arm 28, to move said arm in the direction oppositethat indicated by arrow :0. The pawl is thus caused to rotate theratchet 30 and pulley 26 step by step in the direction required to takeup or shorten the tether 25 and move the levers 19 and 18 and the brakeshoes, through the described connections, in the directions required tolocate the shoes nearer the peripheries of the wheels, and thuscompensate for the wear of the shoes.

The spring 35 abuts at one end on a fixed guide 40, in which the rod 36is movable, and at the other end on a collar 41 attached to said rod.The brake-setting movement of the brake rod compresses the spring 35 andsets it for action, the spring acting automatically when the brake rodis released.

A stop pawl 41 engaging the ratchet 30 limits the movement imparted tothe takeup pulley 26 by the pawl 29.

Figs. 4 and 5 show a different embodiment of the invention adapted to--a sixwheeled truck, although only two of the three wheels at one side ofthe truck are shown. The brake head and beam associated with the thirdwheel (not shown) may be connected by a rod 50 with a lever 18 havingarms of equal length. One of the arms of the lever 18 is connected withthe brake rod 22 having the collar 32. The other arm of said lever isconnected by a rod 23 with the shorter arm of a lever 19" correspondingto the lever 19 and fulcrumed at 21 on an arm 15 which is attached tothe brake beam 5. The longer arm of the lever 19 is connected with thetether 25.

The brake-setting movement of the brake rod 22 first applies the brakeshoe (not shown) connected with the rod 50, and then applies the brakeshoe 9 connected with the lever 19. The wear of the shoe 9 iscompensated for by the means already described in connection with Figs.1, 2 and 3.

In each embodiment of our invention the lever 19 or 19 constitutes abrake lever having a fulcrum which is shift-able by the shortening ofthe tether to compensate for wear of the brake shoes.

Having described our invention, we claim:

1. In a slack adjuster for brakes, a takeup wheel and a ratchet wheelanda pawlcarrying actuating lever therefor all in axial alinement, saidtake-up wheel and said ratchet wheel being fixed with relation to eachother, a rod one end of which is pivoted to said lever and the other endof which is arranged to slide on the brake rod, said slidahle rod beingactuatable by setting movement of the brake rod to carry said lever topotential take-up position, and a spring-pressed rod substantiallyparallel with said slidable rod and pivoted to said lever and arrangedto move said lever to cause take-up movement of said ratchet and take upwheel upon release of the brakes.

2. In a slack adjuster for brakes, a takeup wheel and a ratchet wheeland a pawlcarrying actuating lever therefor all in axial alinement. saidtake-up wheel and said ratchet wheel being fixed with relation to eachother, a rod one end of which is pivoted to said lever and the other endof which is arranged to slide on the brake rod, said slidable rod beingactuatable by setting movement of the brake rod to carry said lever topotential take-up position, a second rod pivoted to said lever anddisposed substantially parallel with said slidable rod and operable by acompression spring to move said lever to cause take-up movement of saidratchet and take-up wheel upon release of the brakes, and means foradjusting the pressure of said compression spring.

3. In a slack adjuster for brakes, the combination with the brake rodand an adjustable member thereon, of a take-up wheel and a ratchet wheeland a pawl carrying actuating lever therefor all in axial alinement,said take-up wheel and said ratchet wheel being fixed with relation toeach 130 said lever to cause take-up movement of said ratchet andtake-up wheel upon release of the brakes.

In testimony whereof we have aflixed our signatures, in presence of twowitnesses.

HERBERT F. WOOD. JOSEPH GULLAGE. Witnesses:

C. F. BROWN, P. W. PEzzETrI.

Copies of this patent may be obtained for five cents each, by addressingthe "Commissioner of Patents. Washington, D. G.

